The letters of the English language, arranged by decreasing frequency, are:
E, T, N, R, I, O, A, S, D, H, L, C, F, P, U, M, Y, G, W, V, B, X, K, Q, J, Z
Playing the Alphabet Game on long car trips as a kid is a good way to acquire an intuitive knowledge of this.
Other language characteristics to look for when using frequency analysis include digraphs, or letters commonly written together.